# Draft California 2012 Integrated Report( 303(d) List/305(b) Report)

# Supporting Information

## Regional Board 6 - Lahontan Region

Water Body Name: | Willow Creek (Lassen County)
Water Body ID: | CAR6372009520020603145810
Water Body Type: | River & Stream

DECISION ID | 20747 | Region 6
Willow Creek (Lassen County)

Pollutant: | Dissolved oxygen saturation
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One of evidence is available in the administrative record to assess this pollutant. One of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. No quality assurance information is available to determine whether this dataset satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. One of three samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20747, Dissolved oxygen saturation | Region 6
Willow Creek (Lassen County)
LOE ID: | 6419
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 1
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled Willow Creek on June 6 2002 and August 20, 2002. Percent saturation of dissolved oxygen at three different stations ranged from 78 to 85.7 percent. One of three samples was in violation of the objective.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide narrative objective states that percent saturation shall not be depressed by more than 10 percent and minimum dissolved oxygen concentration shall not be less than 80 percent saturation.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Three stations were sampled.
Temporal Representation: | Station W-8 was sampled on June 6, 2002. All three stations were sampled on August 20, 2002. .
Environmental Conditions: | Willow Creek is a tributary of the Susan River. It is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses, and for the Spawning, Reproduction and Development uses. Site specific water quality objectives are designated for certain constituents for two stations on Willow Creek in Basin Plan Table 3-9. Both stations with objectives are upstream of the USBLM sampling sites.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 21052 | Region 6
Willow Creek (Lassen County)

Pollutant: | Fecal Coliform
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. No quality assurance information is available to determine whether this dataset satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Samples were collected only in the summer and are not necessarily representative of year-round conditions. 3. None of three samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21052, Fecal Coliform | Region 6
Willow Creek (Lassen County)
LOE ID: | 6413
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 4
Number of Exceedances: | 0
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled Willow Creek in June and August 2002. Concentrations of fecal coliform bacteria in four samples ranged from 0 to 8 colonies per 100 mL. The objective was not violated. (Because the objective requires a minimum of five samples in a 30-day period, log means were not calculated.)
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's water quality objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Three stations (USBLM Nos. W-1, W-4 and W-8) were sampled.
Temporal Representation: | Two sampling runs were made. All three stations were sampled on August 20, 2002. Station W-8, "Willow Creek at Sheep Bridge" was also sampled on June 6, 2002.
Environmental Conditions: | Willow Creek is a tributary of the Susan River. It is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses, and for the Spawning, Reproduction and Development uses. Site specific water quality objectives are designated for certain constituents for two stations on Willow Creek in Basin Plan Table 3-9. Both stations with objectives are upstream of the USBLM sampling sites.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21052, Fecal Coliform | Region 6
Willow Creek (Lassen County)
LOE ID: | 6411
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 4
Number of Exceedances: | 0
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled Willow Creek in June and August 2002. Concentrations of fecal coliform bacteria in four samples ranged from 0 to 8 colonies per 100 mL. The objective was not violated. (Because the objective requires a minimum of five samples in a 30-day period, log means were not calculated.)
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's water quality objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Three stations were sampled.
Temporal Representation: | Two sampling runs were made. All three stations were sampled on August 20, 2002. Station W-8, "Willow Creek at Sheep Bridge" was also sampled on June 6, 2002.
Environmental Conditions: | Willow Creek is a tributary of the Susan River. It is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses, and for the Spawning, Reproduction and Development uses. Site specific water quality objectives are designated for certain constituents for two stations on Willow Creek in Basin Plan Table 3-9. Both stations with objectives are upstream of the USBLM sampling sites.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 21053 | Region 6
Willow Creek (Lassen County)

Pollutant: | Oxygen, Dissolved
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Three of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. No quality assurance information was available to determine whether the dataset used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The dataset used does not satisfy the data quantity requirements of section 6.1.5 of the Policy. All samples were collected on one date. 3. Three of three samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21053, Oxygen, Dissolved | Region 6
Willow Creek (Lassen County)
LOE ID: | 6418
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 3
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled Willow Creek on August 20, 2002. Concentrations of dissolved oxygen at three different stations ranged from 7.42 to 7.78 mg/L.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The water quality objective (Lahontan Basin Plan Table 3-6) is a one-day minimum dissolved oxygen concentration of 8 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Three stations were sampled.
Temporal Representation: | All three stations were sampled on August 20, 2002. .
Environmental Conditions: | Willow Creek is a tributary of the Susan River. It is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses, and for the Spawning, Reproduction and Development uses. Site specific water quality objectives are designated for certain constituents for two stations on Willow Creek in Basin Plan Table 3-9. Both stations with objectives are upstream of the USBLM sampling sites.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 20818 | Region 6
Willow Creek (Lassen County)

Pollutant: | Sediment
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: The Lahontan Basin Plan's narrative water quality objective is an antidegradation based objective that provides that there shall be no increases in suspended sediment concentrations or loads. This pollutant is being considered for placement on the section 303(d) list under section 3.10 of the Listing Policy, which deals with trends in water quality. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence, based on quarterly sampling, is available in the administrative record to assess this pollutant. It consists of a single sample. Suspended sediment concentrations and loads are dependent on flows and can change rapidly over a short time during storm or snowmelt runoff events. Quarterly samples are insufficient to capture these short term events and therefore are insufficient to define natural background suspended sediment concentrations and loads, or to detect trends. Listing Policy Section 3.10 requires that natural background conditions be established. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. No quality assurance information was submitted with this dataset. 2. Sampling frequency was insufficient to establish natural background conditions and therefore does not meet the requirements of Listing Policy Section 3.10. 3. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20818, Sediment | Region 6
Willow Creek (Lassen County)
LOE ID: | 6416
Pollutant: | Sediment
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management collected one suspended sediment sample from Willow Creek on June 6, 2002. There is insufficient information to document background conditions or allow evaluation of change.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide water quality objective states: "The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station, Willow Creek at Sheep Bridge, was sampled.
Temporal Representation: | Station W-8, "Willow Creek at Sheep Bridge" was sampled on June 6, 2002.
Environmental Conditions: | Willow Creek is a tributary of the Susan River. It is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses, and for the Spawning, Reproduction and Development uses. Site specific water quality objectives are designated for certain constituents for two stations on Willow Creek in Basin Plan Table 3-9. Both stations with objectives are upstream of the USBLM sampling sites.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 20832 | Region 6
Willow Creek (Lassen County)

Pollutant: | Specific Conductance
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. No quality assurance information is available to determine whether the dataset used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. None of four samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20832, Specific Conductance | Region 6
Willow Creek (Lassen County)
LOE ID: | 6405
Pollutant: | Specific Conductance
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 4
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled Willow Creek in June and August 2002. Specific conductance values in four samples ranged from 195 to 450 uS/cm. The MCL was not exceeded.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCL) apply to ambient surface waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for specific conductance is 900 microsiemens per centimeter (uS/cm).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Three stations were sampled.
Temporal Representation: | Two sampling runs were made. All three stations were sampled on August 20, 2002. Station W-8, "Willow Creek at Sheep Bridge" was also sampled on June 6, 2002.
Environmental Conditions: | Willow Creek is a tributary of the Susan River. It is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses, and for the Spawning, Reproduction and Development uses. Site specific water quality objectives are designated for certain constituents for two stations on Willow Creek in Basin Plan Table 3-9. Both stations with objectives are upstream of the USBLM sampling sites.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 20833 | Region 6
Willow Creek (Lassen County)

Pollutant: | Temperature, water
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. The water quality objective for temperature is anti-degradation based, and there are insufficient samples to establish background temperature conditions, to document trends, or to determine whether changes in violation of the objective have occurred.. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. No quality assurance information is available to determine whether the dataset used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. There are insufficient background/trend data available to determine whether the objective is being exceeded under Section 3.10 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20833, Temperature, water | Region 6
Willow Creek (Lassen County)
LOE ID: | 6423
Pollutant: | Temperature, water
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 4
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled Willow Creek in June and August 2002. Temperatures in four samples ranged from 17.48 to 23 degrees Celsius.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The relevant language from the Lahontan Basin Plan's temperature objective states: "The natural receiving water temperature of all waters shall not be altered unless it can be demonstrated to the satisfaction fo the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses. For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit ... above or below the natural temperature. For waters designated COLD, the temperature shall not be altered."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Three stations were sampled.
Temporal Representation: | Two sampling runs were made. All three stations were sampled on August 20, 2002. Station W-8, "Willow Creek at Sheep Bridge" was also sampled on June 6, 2002.
Environmental Conditions: | Willow Creek is a tributary of the Susan River. It is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses, and for the Spawning, Reproduction and Development uses. Site specific water quality objectives are designated for certain constituents for two stations on Willow Creek in Basin Plan Table 3-9. Both stations with objectives are upstream of the USBLM sampling sites.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 22514 | Region 6
Willow Creek (Lassen County)

Pollutant: | pH
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: One line of evidence is available in the administrative record to assess this pollutant. The Lahontan Basin Plan's narrative pH objective is a non-degradation objective for waters designated for the Cold Freshwater Habitat beneficial use, and sample numbers are insufficient to establish baseline conditions or detect trends as required under Listing Policy Section 3.10. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. No quality assurance information was submitted with the dataset. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Only one sample is available. 3. It is not possible to determine whether the narrative pH objective was exceeded because the requirements of Listing Policy Section 3.10 were not met. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 22514, pH | Region 6
Willow Creek (Lassen County)
LOE ID: | 6407
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 4
Number of Exceedances: | 2
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled Willow Creek in June and August 2002. Values of pH in four samples rranged from 7.42 to 9.02. Two samples had pH values above 8.5. There is insufficient information to document background conditions or allow evaluation of change.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The regionwide pH objective in the Lahontan Basin Plan states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Three stations were sampled.
Temporal Representation: | Two sampling runs were made. All three stations were sampled on August 20, 2002. Station W-8, "Willow Creek at Sheep Bridge" was also sampled on June 6, 2002.
Environmental Conditions: | Willow Creek is a tributary of the Susan River. It is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses, and for the Spawning, Reproduction and Development uses. Site specific water quality objectives are designated for certain constituents for two stations on Willow Creek in Basin Plan Table 3-9. Both stations with objectives are upstream of the USBLM sampling sites.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):